/
cmcd.js
176 lines (175 loc) · 7.26 KB
/
cmcd.js
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
/**
* @externs
*/
/**
* @typedef {{
* br: (number|undefined),
* d: (number|undefined),
* ot: (string|undefined),
* tb: (number|undefined),
* bl: (number|undefined),
* dl: (number|undefined),
* mtp: (number|undefined),
* nor: (string|undefined),
* nrr: (string|undefined),
* su: (boolean|undefined),
* cid: (string|undefined),
* pr: (number|undefined),
* sf: (string|undefined),
* sid: (string|undefined),
* st: (string|undefined),
* v: (number|undefined),
* bs: (boolean|undefined),
* rtp: (number|undefined)
* }}
*
* @description
* Client Media Common Data (CMCD) data.
*
* @property {number} br
* The encoded bitrate of the audio or video object being requested. This may
* not be known precisely by the player; however, it MAY be estimated based
* upon playlist/manifest declarations. If the playlist declares both peak and
* average bitrate values, the peak value should be transmitted.
*
* @property {number} d
* The playback duration in milliseconds of the object being requested. If a
* partial segment is being requested, then this value MUST indicate the
* playback duration of that part and not that of its parent segment. This
* value can be an approximation of the estimated duration if the explicit
* value is not known.
*
* @property {string} ot
* The media type of the current object being requested:
* - `m` = text file, such as a manifest or playlist
* - `a` = audio only
* - `v` = video only
* - `av` = muxed audio and video
* - `i` = init segment
* - `c` = caption or subtitle
* - `tt` = ISOBMFF timed text track
* - `k` = cryptographic key, license or certificate.
* - `o` = other
*
* If the object type being requested is unknown, then this key MUST NOT be
* used.
*
* @property {number} tb
* The highest bitrate rendition in the manifest or playlist that the client
* is allowed to play, given current codec, licensing and sizing constraints.
*
* @property {number} bl
* The buffer length associated with the media object being requested. This
* value MUST be rounded to the nearest 100 ms. This key SHOULD only be sent
* with an object type of ‘a’, ‘v’ or ‘av’.
*
* @property {number} dl
* Deadline from the request time until the first sample of this
* Segment/Object needs to be available in order to not create a buffer
* underrun or any other playback problems. This value MUST be rounded to the
* nearest 100ms. For a playback rate of 1, this may be equivalent to the
* player’s remaining buffer length.
*
* @property {number} mtp
* The throughput between client and server, as measured by the client and
* MUST be rounded to the nearest 100 kbps. This value, however derived,
* SHOULD be the value that the client is using to make its next Adaptive
* Bitrate switching decision. If the client is connected to multiple
* servers concurrently, it must take care to report only the throughput
* measured against the receiving server. If the client has multiple
* concurrent connections to the server, then the intent is that this value
* communicates the aggregate throughput the client sees across all those
* connections.
*
* @property {string} nor
* Relative path of the next object to be requested. This can be used to
* trigger pre-fetching by the CDN. This MUST be a path relative to the
* current request. This string MUST be URLEncoded. The client SHOULD NOT
* depend upon any pre-fetch action being taken - it is merely a request for
* such a pre-fetch to take place.
*
* @property {string} nrr
* If the next request will be a partial object request, then this string
* denotes the byte range to be requested. If the ‘nor’ field is not set, then
* the object is assumed to match the object currently being requested. The
* client SHOULD NOT depend upon any pre-fetch action being taken – it is
* merely a request for such a pre-fetch to take place. Formatting is similar
* to the HTTP Range header, except that the unit MUST be ‘byte’, the ‘Range:’
* prefix is NOT required and specifying multiple ranges is NOT allowed. Valid
* combinations are:
*
* - `"\<range-start\>-"`
* - `"\<range-start\>-\<range-end\>"`
* - `"-\<suffix-length\>"`
*
* @property {boolean} su
* Key is included without a value if the object is needed urgently due to
* startup, seeking or recovery after a buffer-empty event. The media SHOULD
* not be rendering when this request is made. This key MUST not be sent if it
* is FALSE.
*
* @property {string} cid
* A unique string identifying the current content. Maximum length is 64
* characters. This value is consistent across multiple different sessions and
* devices and is defined and updated at the discretion of the service
* provider.
*
* @property {number} pr
* The playback rate. `1` if real-time, `2` if double speed, `0` if not
* playing. SHOULD only be sent if not equal to `1`.
*
* @property {string} sf
* The streaming format that defines the current request.
*
* - `d` = MPEG DASH
* - `h` = HTTP Live Streaming (HLS)
* - `s` = Smooth Streaming
* - `o` = other
*
* If the streaming format being requested is unknown, then this key MUST NOT
* be used.
*
* @property {string} sid
* A GUID identifying the current playback session. A playback session
* typically ties together segments belonging to a single media asset. Maximum
* length is 64 characters. It is RECOMMENDED to conform to the UUID
* specification.
*
* @property {string} st
* Stream type
* - `v` = all segments are available – e.g., VOD
* - `l` = segments become available over time – e.g., LIVE
*
* @property {number} v
* The version of this specification used for interpreting the defined key
* names and values. If this key is omitted, the client and server MUST
* interpret the values as being defined by version 1. Client SHOULD omit this
* field if the version is 1.
*
* @property {boolean} bs
* Buffer starvation key is included without a value if the buffer was starved
* at some point between the prior request and this object request, resulting
* in the player being in a rebuffering state and the video or audio playback
* being stalled. This key MUST NOT be sent if the buffer was not starved
* since the prior request.
*
* If the object type `ot` key is sent along with this key, then the `bs` key
* refers to the buffer associated with the particular object type. If no
* object type is communicated, then the buffer state applies to the current
* session.
*
* @property {number} rtp
* Requested maximum throughput
*
* The requested maximum throughput that the client considers sufficient for
* delivery of the asset. Values MUST be rounded to the nearest 100kbps. For
* example, a client would indicate that the current segment, encoded at
* 2Mbps, is to be delivered at no more than 10Mbps, by using rtp=10000.
*
* Note: This can benefit clients by preventing buffer saturation through
* over-delivery and can also deliver a community benefit through fair-share
* delivery. The concept is that each client receives the throughput necessary
* for great performance, but no more. The CDN may not support the rtp
* feature.
*/
var CmcdData;